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Diagnosis & Repair

WARNING: This page is about a different car, the 2002 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.
  1. Start engine and warm to engine to normal operating temperature. Ensure A/C and all accessories are off. Apply parking brake. Place transaxle in Neutral. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3 at driver's side of instrument panel. See Figure.
  2. Note location of data link connector No. 1 on end of air intake chamber at passenger's side of engine. See Fig 1. Install Jumper Wire (SST 09843-18020 or SST 09843-18040) between terminals TEI and E1 on data link connector No. 1. See Fig 1. Note engine speed in less than 5 seconds and at more than 5 seconds after installing jumper wire. If difference in engine speed is 100 RPM or less, shut engine off and remove jumper wire. Go to next step. If difference in engine speed is more than 100 RPM, shut engine off. Remove jumper wire and go to step  8.
    Fig 1: Installing Jumper Wire Between Data Link Connector No. 1 Terminals
    G99D52830Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. Check for any loose or defective connections at PCV valve and hose. PCV valve is located on firewall side valve cover at timing belt end of engine. If PCV valve and hose connections are okay, go to next step. If PCV valve or hose connections are defective, repair or replace components as necessary.
  4. Ensure ignition is off. Remove glove box for access to ECM with electrical connectors still installed on ECM. See Figure. Disconnect ECM electrical connector E4. See Figure.
  5. Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 26 (Green/Black wire) at ECM electrical connector E4. See Figure. This is the RSO terminal on ECM. Voltage should be 9-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, check IAC valve operation. See IDLE AIR CONTROL VALVE under IDLE CONTROL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If IAC valve is defective, replace IAC valve. If IAC valve is okay, check for open and short in wiring harness and electrical connectors between EFI main relay, EFI No. 2 fuse (7.5-amp) and IAC valve, and between IAC valve and ECM. See WIRING DIAGRAMS article. EFI main relay may also be referred to as EFI relay. EFI main relay and EFI No. 2 fuse are located in fuse/relay box at driver's side front corner of engine compartment. Repair wiring as necessary.
  6. Check IAC valve operation. See IDLE AIR CONTROL VALVE under IDLE CONTROL SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If IAC valve is okay, go to next step. If IAC valve is defective, replace IAC valve.
  7. Remove IAC valve from throttle body. Inspect IAC valve and passages for carbon build-up and blockage. If a problem exists, repair as necessary. If problem does not exist, replace ECM.
  8. Ensure engine oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, an open or short in A/C signal circuit to ECM may exist. See appropriate article in AIR CONDITIONING & HEATING.
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